1. Field of the Invention
The present invention relates to an internal combustion engine ignition device to be mounted, for example, in a vehicle, and in more detail, to an internal combustion engine ignition device that generates a high voltage for ignition at a secondary coil of an ignition coil by interrupting flow of a current through a primary coil of the ignition coil by means of a switching element.
2. Description of the Background Art
Among conventional internal combustion engine ignition devices, there are such devices in which a time period for detecting an ion current is established by rendering conductive again the switching element connected to the primary coil of the ignition coil, after the interruption of electric flow of a primary current, to thereby cause a secondary current not to flow (for example, see, Patent Document 1).    Patent Document 1: Japanese Patent Application Laid-open No. 2010-121553
In the conventional ignition devices with the above described configuration, there is a problem in that since heat generation of the switching element becomes large when it is rendered conductive again after having been rendered conductive, it is required to suppress heat generation of the switching element itself and to ensure heat dissipation therefor, so that the devices are restricted in its upsizing and its coil-output characteristic.